Hydraulic accumulator



MACK ET AL HYDRAULIC ACCUMULATOR Aug. 26, 1930.

Filed v001;. 24, 1928 2 Sheets-Sheet 1 Zn/en 501's Aug. 26, 1930. MACKET AL I 1,773,821

umnwmc AGCUMULATOR Filed Oct. 24, 1928 2 Shoots-Sheet 2 JrwenfarPatented Aug. 26, 1930 UNITED STATES MARTIN MACK AND WI LHELMGRbTZINGER, OF STUT'IGART -CANNSTATT, GERMANY HYDRAULIG'ACCUMULATORApplication filed October 24, 1928, Serial No. 314,824, and in. GermanySeptember 28, 1928.

Our invention relates to hydraulic accumulators, more especially of thekind in which a piston is arranged for free reciprocation within thecylinder of the accumulator, being acted upon on one side by the liquidand on the other side by compressedair so as to separate the liquid andair spaces. In accumulators of this kind the valves'or slides whichserve to throw the pressure liquid pump in and out of operation, arecontrolled by the piston, as it moves in the cylinder.

In accumulators of this kind, in order to save space, it has beensuggested to mount the piston for free motion on a rod, which could bereciprocated by the piston only the distance which is required tocontrol the valves. However, in these cases the controlling membersstill consumed an inadmissible space and were also exposed to mechanicaldamage.

It is an object of our invention to provide an accumulator of this kind,in which the.

space taken up by the controlling and safety devices is reduced to aminimum, while pipes connecting the accumulator with the valves and thelike are dispensed withaltogether, all the controlling parts beingprotected in such manner as to be safe from injury. Nevertheless thevalves may be operated by hand, if desired. I

We obtain this according to the present invention by accommodating thevalves and the like inthe wall of the accumulator cylinder andpreferably in the bottom thereof, com

munication between the valves and the interior of the cylinder beingprovided by corresponding conduits.

In the drawings aflixed to this specification and forming part thereofthree forms of a hydraulic accumulator embodying our in- 0 vention areillustrated diagrammatically by way of example.

In the drawings, f Figs. 1-3 illustrate the first form, V Fig. 1 beingan axial section of the accumu lator as a Whole, while Fig. 2 is an endview and Fig. 3 a development of a circular section parallel to theaccumulator axis taken on the line AB in Fig. 2.

Fig.4 is an axial section of the bottom part of the second form, and

Fig. 5 is a similar view of the third form.

Referring first to Figs. 1-3, 1 is the accumulator cylinder, 2 is thecompressed air space, 3 is the liquid space and 4- is the pistonseparating them. 5 is the piston rod and 6 and ,7 are two abutmentsfixed to the rod and serving, when acted upon by the movable piston 4,to displace the rod 5 in one or the other direction. In this case therod 5 having a nut 8 mounted at its bottom end will act on the hollowcontrol member 10. 9 is a stuffing box through which the rod 5 extends.On the outer end of the control member'lO is mounted a controlling disc11 which projects above the pins of the valves, which are disposed inthe bottom of the cylinder 1 with their axes in parallelto the cylinderaxis.

The manually operated valve 12 serves for throwing the apparatus in andout of operation, respectively. 13 is a valve serving to connect-theliquid space 3 of the cylinder through conduit 14with another conduit 15leading to the cylinder of a servomotor or to the means for reversingthe valve of the pump (not shown) which forces liquid intothe cylinderthrough pipe 16. V 17 is a valve serving to connect the cylinder of theservomotor with the conduits 18 and 19, the latter serving as anexhaust. 20 is a safety valve which will connect the liquid space of thecylinder with the exhaust, whenever the apparatus should get out oforder.

The operation of this device is as follows:

After the pump has forced a predetermined quantity of liquid into theliquid space 3, the piston 4 being displaced by the liquid will meet theabutment 6, thereby carrying along rod,5 and nut 8 andthrough thislatter also the hollow control member 10 and disc 11. This disc willfirst act on the projecting pin of valve '13 and with the aid oftheservomotor or the pump valve will stop the operation of the pump; If forany unforeseen reason the pump should still continue operating, disc 11would then act on thepro-jecting pin of valve 20, whereby theaccumulator would be opened towards'the exhaust.

1 On the pump having come to a standstill, the pressure liquid in thecylinder will gradually be consumed, the piston being gradually shiftedtowards the abutment 7 and carrying it along together with rod 5,Whereby nut 8 is moved into contact with the outer end of the controlmember 10, which is now moved to the left together with disc 11. Thevalve 13, being released by disc 11 will now be closed under the actionof the pressure in the cylinder. In moving to the left, disc 11 willcarry along the in of valve 17 by means of an abutment 21 n ounted onthe pin, Whereby the liquid press; between the accumulator and theservomotor or the controlling piston is released so that this pistonwill move backwards under spring action and is enabled to throvv thepump in again.

In the modification illustrated in Fig. 4 the valves 13, 17 and 20 aredisposed within the bottom of cylinder 1 in a position at right anglesto its axis and are controlled by a control member 22 having cam facesformed thereon which are in contact with the valve pins. These cam facesare formed in such manner that vhenever the piston 4 approaches theright end position, Without, however, having reached it, the pin ofvalve 13 Will be lifted While valve 17 which controls he exhaust fromthe pump valve or controlling piston, is closed. \Vhile these valves arebeing acted upon, the pin of the safety valve 20 is still spaced fromits cam on the controlling member so far that it will be lifted only ifthe other valves have been operated and the piston 4 should stillcontinue on its stroke.

In the modification illustrated in Fig. 5 the valves are controlled by aslide 1O which is operated by the rod 5 as described With reference toFigs. l t, the valves being replaced by a system of conduits controlledby the slide 10 in a manner Well known per se.

\Ve wish it to be understood that We do not desire to be limited to theexact details of construction shown and described for obviousmodifications Will occur to a person skilled in the art.

In the claims a'llixed to this specification no selection of anyparticular modification of the invention is intended to the exclusion ofother modifications thereof and the right to ailasequently make claim toany modification not covered by these claims is expressely reserved.

W'e claim .i, Hydraulic accumulator comprising a. cylinder, a piston inthis cylinder freely movable for reciprocation. valves in the bottom ofsaid cylr ed means arranged for op eration b said piston. forcontrolling said valves.

2. Hydraulic accumulator comprising a cylinder. :1 piston. in thiscylinder freely movable for reciprocation, valves in the bottom of saidcylinder and a rod associated with said piston and movable axially insaid cylinder, said rod being arranged to control said valves.

3. Hydraulic accumulator comprising a cylinder, a piston in thiscylinder freely movable for reciprocation, valves including a safetydevice in the bottom of cylinder and means arranged for operation bysaid piston for controlling said valves.

l. Hydraulic accumulator comprising a cylinder, a piston this cylinderfreely movable for reciprocation, valv "s e bottom of said cylinder andarranged at an angle to the cylinder axis and means arranged foroperation by said piston for controlling said valves.

5. Hydraulic accumulator comprising a cylinder, a piston in thiscylinder freely movable for rcclproca es in the bottom of said c" wecfor operation by said piston said valves, said valves bei o be operatedautomatically and another manually operable valve in said cyli derbottom.

In testimony v ereof \ve affix our signatures.

MAI- TEN MACK. IVILHELM GROTZINGER.

